Cut each orange in half in a saw-tooth pattern. Remove orange sections and reserve. Clip membranes inside orange shells and remove. Place orange shells in freezer until thoroughly chilled. Combine orange sections with remaining ingredients and mix thoroughly. Spoon mixture into prepared orange shells. Return to freezer for at least 3 hours. Remove from freezer 30 minutes before serving. Extra orange mixture may be frozen in muffin tins lined with paper baking cups.